The present invention relates to a light-sensitive material which has high sensitivity and storage stability, and can be rapidly processed and, more particularly, to a highly sensitive and stable color photographic light-sensitive material which contains a light-sensitive or silver chlorobromide emulsion and in which silver halide is efficiently used.
Color photographic light-sensitive materials are used at present in increasing quantities. Therefore, it is demanded that these materials be developed in a simple method in a short time. At the same time, the quality of the images is required to be both high and uniform. A silver iodobromide emulsion containing 4 to 20 mol % of silver iodide is generally used in a color photographic light-sensitive material, while a silver chlorobromide emulsion is generally used in a color print material. The silver chlorobromide emulsion has lower sensitivity than silver iodobromide emulsion; it cannot easily processed to a high-quality image; and it can serve to achieve rapid color development.
Silver chloride or silver chlorobromide grains, especially, cubic grains having the (100) crystal plane can be processed rapidly and easily, but they cannot readily undergo chemical sensitization or spectral sensitization. The sensitivity of these grains decreases with time, and these grains tend to cause fogging. Several proposals have been made, all with the air of solving these problems. Japanese Patent Application (OPI) No. 48-51,627 and Japanese Patent Publication No. 49-46,932 describe methods in which water-soluble bromide or iodide ions are added after a sensitizing dye has been added to a silver halide emulsion. Japanese Patent Application (OPI) Nos. 58-108,533 and 60-222,845 describe methods in which bromide and silver ions are simultaneously added to silver halide grains having a high silver chloride content, to form layers containing 60 mol % or more of silver bromide on grain surfaces. In a similar proposed method, a layer containing 10 to 50 mol % of silver bromide is formed over all or part of the surface of each grain. In still another method as described in Japanese Patent Publication Nos. 50-36,978 and 58-24,772, U.S. Pat. No. 4,471,050, and West German Patent Application (OLS) No. 3,229,999, bromide ions are added to a silver halide having a high silver chloride content, or else bromide and silver ions are simultaneously added thereto, to convert the halogen, thereby to obtain multiphase grains such as double-structured (i.e., a core and a shell) grains or junction-structured grains. These conventional methods cannot produce color photographic light-sensitive materials which have a satisfactory sensitivity and other satisfactory properties.
A method of chemically sensitizing an emulsion containing much silver chloride is to use sulfur along with a solvent for dissolving silver halide, as described in Japanese Patent Application (OPI) No. 58-30748. According to another chemical sensitization method, as described in Japanese Patent Application (OLS) No. 58-125,612, the pAg and/or temperatures during sensitization by sulfur are controlled in a two-step manner. However, neither of these two methods provides a product having a sufficiently high sensitivity for use as light-sensitive materials for photographing.
Those skilled in the art have thought it necessary to provide a method of easily and quickly processing color photographic light-sensitive materials, which requires a small number of process baths and a small amount of replenisher.
The processing of color negative photographic light-sensitive material consists of a wet process and a drying process continuous thereto. Processing time has been shortened considerably the by introduction of the C-41 process formulated by Eastman Kodak Co, the wet process, however, still takes as long as 17 minutes and 20 seconds to complete. In the case of the rapid process CN-16Q for small laboratories, available from Fuji Photo Film Co., Ltd., processing still takes as long as 9 minutes and 50 seconds.
In order to improve the existing systems of color negative material and color paper to satisfy the users' needs, the development time must be shortened. The present inventors aim at essentially solving this problem. An existing negative film for photographing using a silver iodobromide emulsion maximally utilizes the advantages (e.g., high sensitivity, and an interimage effect) of silver iodide. However, since the film contains silver iodide, the developing time cannot be shortened. More specifically, iodide irons in the desiliverizing solution retards bleaching and fixing of developed silver, inevitably making it impossible to process the materials rapidly or to reduce the replenisher.
The present inventors conducted extensive studies with the object of increasing the sensitivity of a silver chlorobromide emulsion having a high silver chloride content, and to decrease the incidence of reciprocity failure. Optimal combinations of various methods of forming silver halide grains and various chemical sensitization methods were explored in order to attain the present invention.